You'll find different opinions on how to measure output. The cheapest and most widely accepted (from what I read) on this forum is to take a 2 Liter plastic pop bottle and measure and mark it so you know exactly how much water it holds. Get a bucket so you can submerge the bottle. Fill the bucket with water then fill the pop bottle up with the water. Then, turn the bottle upside down, inverting it in the bucket about an inch or two under the water level in the bucket. Take the output hose from the Gen and stick it up into the entrance to the upside down bottle. Turn the Gen on and time how long it takes for the gas to completely displace the water in the bottle. Your measurements should give you the liters per minute. Check out the link here to see an example (close enough anyway): http://www.youtube.com/watch?v=NwMiIHieTQ0

You'll find different opinions on how to measure output. The cheapest and most widely accepted (from what I read) on this forum is to take a 2 Liter plastic pop bottle and measure and mark it so you know exactly how much water it holds. Get a bucket so you can submerge the bottle. Fill the bucket with water then fill the pop bottle up with the water. Then, turn the bottle upside down, inverting it in the bucket about an inch or two under the water level in the bucket. Take the output hose from the Gen and stick it up into the entrance to the upside down bottle. Turn the Gen on and time how long it takes for the gas to completely displace the water in the bottle. Your measurements should give you the liters per minute. Check out the link here to see an example (close enough anyway): http://www.youtube.com/watch?v=NwMiIHieTQ0